Web accumulator



March 17, 1953 c. HORNBERGER 2,631,847

WEB ACCUMULATOR Filed April 19, 1949 TII CLARENCE L. HORNBERGER L., www

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Patented Mar. 17, 1953 WEB ACCUMULATOR Clarence L. Hornberger, Manheim Township, Lancaster County, Pa., assignor to Armstrong Cork Company, Lancaster, Pa., a corporation of Pennsylvania Application April 19, 1949, Serial No. 88,420

Claims.

This invention relates to a web accumulator and more particularly to an accumulator for use in the processing of sheet material where the material is supplied to the accumulator intermittently and withdrawn from the accumulator continuously.

In the manufacture of sheet material such as floor and Wall coverings, it has been common practice to employ accumulators between various processing steps so that a reserve supply of material is available to furnish a continuous supply to the next succeeding processing operation, should there be an interruption in the preceding operation.

The accumulators commonly used for this purpose comprise a series of rollers placed horizontally on the top of a rigid framework. In some instances the position of the rollers is fixed, and in other instances the rollers are slidable horizontally. At the bottom of the structure there is provided a vertically movable cradle carrying a series of rollers corresponding to the rollers at the top of the machine. This cradle is supported entirely by the sheet material in the accumulator. If the rate of feed into the accumulator is greater than the rate of withdrawal from the device, the cradle descends to the bottom of the structure. In the event the speed of withdrawal is greater than the input speed, the cradle is pulled up toward the top of the structure.

One of the chief disadvantages of the prior art device is a lack of a safety device to prevent the iioating cradle from crashing to the bottom of the structure in the event the sheet material is torn. Another disadvantage of a structure of this type is the diiculty experienced in starting a new run of material through the accumulator inasmuch as the cradle is at the bottom of the device at the start of such operation. This requires a great deal of time in threading the goods around the rollers at the top and bottom of the accumulator. It should be borne in mind that in accumulators suitable for handling sheet material such as floor and wall coverings the distance between the top and bottom rollers is approximately thirty feet.

In order to overcome the disadvantages of the prior art structure described above, I have provided an accumulator which comprises a variable counterweight for the cradle, the counterweight being attached to the cradle by means of a chain which passes over a sprocket, the speed of which may be controlled to prevent the cradle from descending at a rapid rate of speed in the event the material breaks.

I have also provided mecha 2 anism whereby the cradle may be mechanically lifted to the top of the structure to facilitate threading material through the accumulator at the start of a run.v With a counterweight device of this type, the greater portion of the weight of the cradle is balanced by the counterweight.

In order that my invention may be more readily understood it will be described in connection with the attached drawing in which:

Figure 1 is a top plan view of the device of my invention;

Figure 2 is a side elevational view of the device;

Figure 3 is an enlarged view of the drive mechanism employed in operating the safety device; and

Figure 4 is a sectional View taken on the line IV--IV of Figure 2.

Referring to Figures 1 and 2 of the drawing, there is shown a rigid framework or superstructure 2 comprising four upright corner members 3 and a plurality oi. bracing cross members 4. At the top of the machine there are disposed two heavier load-bearing cross members 5. Rotatably journaled in the cross members 5 are rollers 6 which are positioned at a horizontal right angle to the cross member 5. A cradle 'I which is capable of movement in a Vertical direction is mounted within the structure 2 and is guided by pinion gears 8 riding on gear rack trackways 9 provided on the upright members 3. In place of the pinion gears 8 I may use small rollers which ride on smooth trackways disposed on theA inside surface of the uprightmember 3.

The cradle 1 comprises two cross members I0 in which rotatable rollers l! are journaled, said rollers l! being disposed at a horizontal right angle with respect to the cross members I0. In Figure 2 the accumulator is shown carrying fourteen strands of sheet material designated by the numeral I 2. When the device is substantially lled as shown in this view, the cradle 'l is close to the bottom of the device.

The material is fed into the machine by passing it between two positively operated feed rollers I3 and I4 which are rotated by means of a motor not shown. The material is pulled out of the machine by pull-out rolls l5 and I6 which are also operated by a motor not shown.

Mounted on the top of the superstructure is a constant speed reversible motor i1 which is connected by a coupling I8 to a worm gear reducer 19. The output shaft 2|) of the reducer IQ-carries a one-way over-riding clutch 2l of conventional construction. This clutch is effective for coupling the motor l1 with the cradle 1 to elevate the cradle upon rotation of the motor in one direction to bring the cradle to the top of the superstructure to facilitate threading of the cradle. Another function is to control the downward movement of the cradle upon rotation of the motor in the opposite direction, particularly in the event of a break in the web I2. Its third function is to hold the cradle in a desired fixed position; for instance, in threading the cradle upon the start of a run or in the event of a failure of the motor I1 or the coupling I8. During the normal operation of the accumulator the clutch 2| functions to permit the cradle to rise and fall'unrestrictedly when the input and output are not exactly matched.

Mounted upon the loose or overriding element 22 of the clutch 2| is a double chain sprocket 23. A cross shaft 24 is journaled in bearings 25 mounted on the frame mem-bers 5. This cross shaft 24 has double sprockets 2E which are connected by chains 21 to the sprockets 23. The shaft 24 also has affixed to it sprockets 28, one adjacent each side member as shown in Figure 1. Chains 29 which are attached to the cradle l on opposite sides are trained upon the sprockets 28 and carry counterweights 30.

VThe combined weight'of the two counterweights is preferably about 60% of the weight of the cradle. It will be understood, of course, that the counterweights may be varied depending on the nature of the sheet material being processed. For example, if arelatively lightweight sheet is being run, a heavy counterweight is used tc carry a greater percentage of the weight of the cradle, thereby placing less strain on the material. If a relatively heavy sheet material is being run, the weight may be decreased so that the cradle will place the proper amount of tension on the material.

In order to prevent the possibility of the chains 29 disturbing the balance between the counterweights and the cradle, it is desirable to make the chains 29 continuous chains having the counterweights 30 attached thereto. This is accomplished by placingidler sprockets 3l on the lowermos't cross member 4 of the superstructure. In an arrangement of this kind weight of the chain attached to the cradle will be the same as the weight of the chain attached to the counterweight, regardless of the relative position of the two. The counterweights 30 are preferably placed between two L-shaped guides 32 to prevent the weights from oscillating.

The driven element of the clutch 2I is affixed to the' output shaft 20 of the worm gear reducer. The reducer is driven at constant speed, approximately 33.5 R. P. M., and the clutch 2l being capable of overriding in one direction only permits the cradle to rise at will in the event the output from the accumulator through the pull-out rolls I5 and I6 is greater than the input through the feed rolls I 3 and I4. The clutch 2I is so adjusted that normal downward movement of the cradle 'l may be accomplished by free movement of the overriding element 22 of the clutch to accommodate the normal excess of input through rolls I3 and I4 over the output through rolls i5 and I6. In normal operation it is desirable to have the accumulator full; and this is accomplished by having an input speed about 50% greater than normal output speed. with an electrical control for matching the input speed with the output speed when the accumulator is full.

The clutch is set, however, to bring the overriding element 22 into lixed relationship with the driven element upon downward movement of the cradle at a rate greater than the 50% accelerated input speed would permit. Thus should the web I2 break and `the cradle start to fall, its rate of fall would be fast; and the two clutch elements would be connected together. Since the driven element is fixed to the shaft 2li of reducer I9, the rate of rotation of the clutch element 22 to which the cradle-supporting mechanism is connected would be limited by the speed of rotation of the shaft 20 of the reducer I9. Thus the cradle would be lowered slowly and would not be damaged.

In order to elevate the cradle by the motor Il, its direction of rotation is reversed, thereby reversing the direction of rotation of the driven clutch element. Since the clutch is of the oneway type and is operative only when the driven element rotates in the opposite direction, the two clutch members will immediately engage and the shaft 2li will be rotated through the double chain 29 and sprockets 23 and 26. This will elevate the cradle. An electrical control may be provided to stop the motor I1 when the cradle reaches the desired upper position. The worm gear arrangement in the reducer I9 will holdthe unit against movement, even though the motor be stopped.

Upon completion of the threading of the web into the accumulator, the motor will be restarted in its normal direction; and the cradle will fall as the rate of input of the web exceeds the output from the accumulator until the cradle again assumes the position adjacent the bottom with the accumulator full. Then the speed of input and output will be matched.

Figure 4 is a cross-sectional View locking down on the movable cradle 'l showing the relative position of the various elements during the operation of the device.

It will be clear from the above disclosure that I have provided a web accumulator having incorporated therein certain novel features to prevent damage to the device which might be occasioned by the cradle crashing to the bottom of the device in the event a strand of the material is broken, and it will also be clear that I have provided a device in which threading a new run of material through the same is greatly facilitated by means of mechanism for lifting the cradle to the top of the machine at the start of a run.

While I have illustrated and described a certain preferred embodiment of my invention, it will be understood that the same is not so limited, but may be otherwise practiced within the scope of the following claims.

I claim:

1. An accumulator comprising in combination two series of companion rollers about which a web mayL be threaded in a circuitous path from a feed-in end to an outgoing end, one of said series of rollers being mounted -on a cradle supported by the web, a counterweight connected to said cradle, and an overriding clutch, one element of which is continuously rotated by a constant speed motor and the other element of which is operated by the means connecting the counterweight to the cradle.

2. An accumulator comprising in combination two series of companion rollers about which a web may be threaded in a circuitous path from a feed-in end to an outgoing end, one -of said series of rollers being mounted on a cradle supported by the web, a counterweight connected to said cradle by means of a chain, and an overriding clutch, one element of which is continuously rotated by a constant speed motor and the other element of which is operated by the chain connecting the counterweight to the cradle.

3. An accumulator comprising in combination two series of companion rollers `about which a web may be threaded in a circuitous path from a feed-in end to an outgoing end, one of said series of rollers being mounted on a cradle supported by the web, and an overriding clutch, one element of which is continuously rotated by a constant speed mot-or and the overriding element of which is operated by a drive chain connected to said cradle.

4. An accumulator comprising in combination two series of companion rollers about which a web may be threaded in a circuitous path from a feed-in end to an -outgoing end, one of said series of rollers being mounted on a cradle supported by the web, said cradle being capable of vertical movement as the length of the web on the accumulator Varies, a constant speed motor mounted on the device, a rotatable shaft connected to said motor by means of an overriding clutch, said shaft being capable of free rotation at speeds less than the speed of the constant speed motor, but being operated by the motor through the clutch when the speed of the shaft reaches that of the motor, and means connecting said cradle with said shaft.

5. An accumulator comprising in combination two companion rollers about which a web may be threaded in a circuitous path from a feedin end to an outgoing end, one of said rollers being mounted on va bearing member supported by 'the web, a counterweight connected to said bearing member, and an overriding clutch, one element of which is continuously rotated by a constant speed motor and the other element of which is operated by means connecting the counter-weight to the bearing member.

CLARENCE L. I-IORNBERGER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,637,892 Benner etal Aug. 2, 1927 2,010,122 Wikle Aug. 6, 1935 2,242,751 McFarland May 20, 1941 2,253,076 Jones Aug. 19, 1941 2,280,943 Ferm Apr. 28, 1942 

